Return-Path: Content-Type: text/plain; charset=us-ascii Mime-Version: 1.0 (Mac OS X Mail 7.3 \(1878.6\)) Subject: Re: BLE Delayed encryption change using From: Marcel Holtmann In-Reply-To: <002a01cfcc7d$8d290dd0$a77b2970$@lampreynetworks.com> Date: Tue, 9 Sep 2014 15:44:02 -0700 Cc: linux-bluetooth@vger.kernel.org Message-Id: References: <001301cfc950$ecd06240$c67126c0$@lampreynetworks.com> <3A0E8851-3F10-40A4-A5E8-43BCC727D053@holtmann.org> <002a01cfcc7d$8d290dd0$a77b2970$@lampreynetworks.com> To: Caleb Reinhold Sender: linux-bluetooth-owner@vger.kernel.org List-ID: Hi Caleb, >>> I am attempting to reconnect to a BLE glucometer with gatttool after >>> pairing with bluetoothctl. A quick connection update seems to cause a >>> large delay (around a minute) in the transmission of the LL_ENC_REQ. >>> >>> Description: >>> Attempting to connect to an agent which after connecting immediately >>> sends an L2CAP update connection parameters request with minimum >>> connection interval set to 20 ms, and maximum connection interval set to > 40 ms. >>> Increasing both values by 100 ms causes the problem to stop being > generated. >>> >>> The problem happens only if the dongle using the Broadcom BCM20702 >>> chipset is used, using a CSR8510 A10 dongle I cannot generate this >>> issue. I am using BlueZ 5.22, using Linux kernel 3.10.17. The hardware > platform is a Utilite. >> >> try using a 3.17-rc3 kernel. We added storing of the connection parameters. > New connections >> will then use the previously requested connection parameters when > establishing the connection. >> Which means the peripheral does not have to request connection updates on > every connection. > > According to the HCI dump I am not using the saved parameters. I see the > updated parameters getting saved, but the outgoing connection appears to not > be using them. if you run btmon, do you see a mgmt command that indicates that the parameters are actually send to userspace. I think at the moment, we only really store the parameters for devices that are a) in our device list or b) we have paired with. Regards Marcel